1. Technical Field
The present invention relates to a valve which regulates a flow of liquid in a flow pipe and a construction machine with the valve.
2. Background Art
There are many flow pipes which are provided with various valves for regulating flow of liquid. For example, Japanese Utility Model Application Publication No. H2-23056 discloses a hydraulic excavator including a front attachment with a tip portion to be connected to a special working implement such as a crusher can be mounted, a high-flow-rate pipe disposed along the front attachment to supply hydraulic liquid to the special working implement, and a stop valve provided downstream of the high-flow-rate pipe. The stop valve is opened when the special working implement is mounted to the front attachment and is otherwise closed.
As a valve such as the stop valve which is provided in the flow pipe, known is one shown in FIG. 8, namely, a valve 110. The valve 110 has a valve element 111, which is formed with a flow-path hole 113, and a block 112 which is a holding member for holding the valve element 111 so as to allow the valve element 111 to be rotated about a rotational axis X orthogonal to the flow-path hole 113. The valve element 111 is provided with a rotary plate 115 provided at an upper portion of the valve element 111, to which a rotational operation is applied to change the direction of the flow-path hole 113, the flow path thereby being opened or closed. Specifically, the block 112 includes an inlet port 121, which is connected to an upstream section of the flow pipe, and an outlet port 122, which is connected to a downstream section of the flow pipe.
As shown in FIG. 9, the rotary plate 115 is fixed to the holding member 112 through a bolt 117, thereby allowing the valve element 111 to be locked in an open position and in a close position. This structure, while having an advantage of reliably fixing the position of the valve element 111, requires attachment/detachment of the bolt 117 with respect to the block 112 for every open/close switching, leading to reduced working efficiency. This inconvenience might be avoided by simplification or omission of the structure for locking the valve element 111 in the open position and the close position; however, either of the simplification and the omission could allow the valve element 111 in the open position to be displaced toward the close position to reduce an opening area or close the valve.